Expert Speak: How to Reduce AC Cost & Make Homes Energy Efficient

Architect Sangeet Sharma offers his expert views on how passive cooling works and how to integrate it in building design

Pooja Khanna Tyagi 18 October 2021

Houzz India Contributor. An Architect , Interior Designer, Valuer, a Marathon Runner, and love Writing Poetry and Creative Stories on Building Design. Have been practicing since the year 2000 with specialization in the field of Corporate Interiors with projects extensively published in journals of national repute. Recently honoured with the reputed A3 Foundation award for Journalism for the year 2016 an for architectural poetry in the year 2018. Currently practicing and residing in Delhi and Noida. Website: www.khannaenterprise.com, Email: poojakhanna224@gmail.com, M:9891993392

Houzz India Contributor. An Architect , Interior Designer, Valuer, a Marathon Runner,... More

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Passive cooling is a natural cooling technique that is incorporated into the design of the building to create a comfortable indoor environment. Passive cooling not only reduces the heat gain within the building but also removes excess heat from the structure during intense months. Therefore, passive cooling is a great way to create a climate-responsive building design that reduces the air-conditioning costs and makes the building energy-efficient.

Expert advice: Architect Sangeet Sharma of SD Sharma & Associates, Chandigarh

Kumar Moorthy & Associates

External sun-shading
“External shading of the windows, roof and walls is the most popular way to prevent indoor heat gain. I particularly use louvres as an element of passive cooling, which is my architectural idiom and that of the city of Chandigarh,” says Sangeet Sharma.

The fixed sun-shading options include deep balconies, recessed windows or a continuous overhang, just as in this example.
Trees around the building are very effective in shading the walls. Plants should be grown in the internal courtyards, as they enable cooling by transpiration – the leaves release water vapour, reducing the temperature of the surrounding air.
Adjustable shading options include venetian blinds, curtains, retractable awnings and manually adjustable louvres in windows.

Find an architect in the Houzz directory to design a naturally cool home

Insulated walls and ceiling
A well-insulated home prevents the transfer of heat through the roof and the walls. “Passive cooling requires the building design to incorporate techniques in the building itself, such as cavity walls, roof insulation and other reflective building materials that may help the building for additional cooling without depending on technology,” suggests Sharma.

A reflective roof coating or a light-coloured roof reflects a lot of the heat from solar radiation.
A roof garden cuts off heat, as the lawn and the mud in the potted plants absorb the heat that hits the roof.
Cavity walls are excellent insulators. Using hollow bricks for the construction of exterior walls gives better thermal insulation than solid walls. The air in the hollow bricks prevents transmission of heat from the outdoors into the indoors.
Finish the windows with low-emissivity coating and films to reduce heat loss through the window.

Note: Consider a false ceiling for insulating the rooms that are immediately below the roof. The air gap between the true ceiling and false ceiling works as an insulating layer that prevents indoor heat gain.

How to Beat the Summer Heat by Keeping the Roof Cool

Kumar Moorthy & Associates

Water feature
Sharma says, “Evaporative cooling is a very good passive cooling technique, in which the outdoor air is cooled by evaporating water before it enters the building.”

Introduce a pool, fountain, waterfall or any other water feature within courtyards or the outdoors. “Evaporative cooling is only effective in a dry climate with low humidity levels, because only dry air can absorb water vapour,” adds Sharma.

Get plants and fountains from Houzz products

Shamanth Patil Photography

Cross ventilation
“It is recommended to orient the building with respect to the sun’s path and the prevailing wind patterns, so as to make optimum utilisation of the sun and increase the energy efficiency of the home,” says Sharma.

Cross ventilation ensures good air movement from one side of the home to the other, it brings in fresh air, removes airborne pollutants and moisture from the home.
Strategically position the windows of the home in the direction that brings in maximum breeze. This is an effective way to cool the indoors by removing hot air and replacing it with cool air.
Passive ventilation uses doors, windows, vents, louvres and other openings to let fresh air enter the home.

Courtyards are great at cooling a home – see these inspiring photos on Houzz

“An efficient building design depends partly on air-conditioning and partly on passive cooling to reduce the overall load and cost of cooling,” Sharma says. “Young architects should integrate passive cooling techniques within their building designs instead of totally depending on technology and air-conditioning. If you see our older buildings of modern architecture, there are so many elements of passive cooling, which have been well integrated with modern technology,” he says.

Khosla Associates

Read more:
9 Ways to Say NO to the AC and Reduce Electricity Costs
9 Stunning Courtyards That Soak Up the Sun

Tell us:
What passive cooling techniques have you incorporated within the design of your home? Share in the Comments section below.

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preeti kumar

Old government houses strewn across the country had many such features. Comparatively small with few rooms, they featured deep verandahas front and back, small windows in opposing walls, ventilators and high ceilings. Then modernism and technology took over- verandahas got converted into additional rooms, ventilators were boarded and shut, false ceilings built to accommodate ACs and round the clock lights for poorly lit rooms. Lawns and gardens became cemented patios, hedges were replaced with brick walls and unruly trees trimmed and felled to accommodate parking spaces. We need a new blueprint for making our homes sensitive to our environment, but tuned to our modern needs.

1 Like 21 October 2021 at 11:34pm